Telephone apparatus.



No! 830,272. PATENTED SEPT. 4, 1906. D. H. WILSON.

TELEPHONE APPARATUS.

APPLICATION FILED JAN. 2, 1906.

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UNITED STATES PATENT OFFICE.

DAVID H. WILSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO ROBERT BINES,

OF CHICAGO, ILLINOIS.

TELEPHONE APPARATUS.

Specification of Letters Patent.

Patented se t. 4. 1906.

Application filed January 2, 1906. Serial No. 294,251.

, panying drawing, wherein the figure is a view showing diagrammatically a construction embodying the invention.

Referring now to the figure, there is shown a transmitter A, connected in a circuit containing a source of current-supply B. This transmitter-circuit contains two coils A B, which are connected in multiple, said coils being wrapped about the iron cores A B These iron cores also contain coils C C, which are connected in series and whichare also connected with the main line D. Between the cores A B are two cores E and F, preferably magnetically insulated from the cores A B In this construction the ends of the cores A and B which are opposite each other, are unlike poles, this result being secured by the winding of the coils thereon. In other words, the cores E and F are interosed between unlike poles of the cores A B he cores E and F are provided with the coils E-F. Both these coils are connected to the receiver G. It will be seen that the receiver is connected in circuit with two coils each wound upon a separate core upon which there are no other coils and that the circuit containing the receiver is electrically indeendent of the transmitter-circuit and the inc-circuit and contains no battery or other electrical generator.

In operating the device the operator talks into the receiver at one end of the line. A

talking-current is then generated in the main of the variation of the current the magnetism of the core is varied. This induces a talkingcurrent in the coils E and F, and this current is conducted to the receiver and there reproduced into speech.

In view of the fact that the receiver-circuit and coils are electrically independent of the main line and the transmitter-circuit thespeech is reproduced entirely free from the extraneous inductive effects on the line, and hence absolute clearness is secured.

I claim- 1. A telephone apparatus comprising a transmitter-circuit, two separated iron cores about which a portion of said transmittercirouit is wound, a main line-circuit having a portion also wound about said cores, two separated iron cores interposed between said first-mentioned cores each provided with a coil, and a receiver connected in circuit with both of said coils.

2. A telephone apparatus comprising a transmitter-circuit, two separated iron cores about which a portion of said transmitter-circuit is wound, a main line-circuit having a portion also wound about said cores, the windings being such that the opposed poles of said cores are unlike, two separated iron cores interposed between said first-mentioned cores, each provided with a coil, and a receiper connected in circuit with both of said 001 s.

3. A telephone apparatus comprising a transmitter-circuit, two separated iron cores about which a portion of said transmitter-circuit is wound, a main line-circuit having a portion also wound about said cores, the windin being such that the opposed poles of said cores are unlike, two separated iron cores interposed between said first-mentioned cores,

each provided with a coil, and a receiver connected in circuit with both of said coils, the several cores magnetically insulated from DONALD M. CAnrER, EDWARD T. Wan. 

